The present invention relates to a stapler used to staple a stack of paper discharged from an image forming device such as a photocopier or a printer.
The following is an explanation of the stapling operation of a prior art stapler with reference to FIG. 1 and FIG. 2. The sheet of staples S shown in FIG. 1 consists of a series of single staples. The sheet of staples S is rolled up and housed in the housing unit 50a of the cartridge 50. Here, the sheet of staples S extends from the extraction opening 50b in the housing unit 50a. The cartridge 50 mounted in the housing unit 50a has a pair of walls 50c, 50c separated at a specific interval as an extension of the extraction opening 50b. The interval between the walls 50c, 50c is roughly equal to the width of the sheet of staples S. Therefore, the sheet of staples S extending from the extraction opening 50b passes between the walls 50c, 50c in the direction of the arrow shown in FIG. 1.
Guides 51, 51 are placed on the cartridge 50 to prevent the sheet of staples S from riding up from the extraction opening 50b. In other words, the sheet of staples S is restrained widthwise by wall 100c and prevented from riding up by the guides 51, 51 so as to travel in the direction of the arrow. As shown in FIG. 1, a plate 52 is extended between the side walls 50c, 50c, and a reverse motion stopping tab 52a is formed on both ends of the plate 52. The reverse motion stopping tab 52a makes contact with the sheet of staples S to prevent the sheet of staples S from moving in the direction opposite to the arrow back into the housing unit 50a. In other words, the sheet of staples S moves in the direction of the arrow shown in FIG. 1, and is not allowed to return to the housing unit 50a. 
The cartridge 50 is mounted in the main body of the device 70 shown in FIG. 2, and the pressure unit 53 formed in the cartridge 50 is brought to bear when the cartridge is mounted on the spring plate 55 on the advancing unit 54 of the main body of the device 70. The pressure from the spring plate 55 keeps the advancing unit 54 in the position shown in FIG. 2. When the driver 56 applying the staples is lowered from the position shown in FIG. 2, the protrusion 56a on the driver 56 is brought to bear on the protruding plate 54a formed on the advancing unit 54. Therefore, the lowering force of the driver 56 is communicated to the advancing unit 54 via the protrusion 56a and the protruding plate 54a, and the advancing unit 54 resists the spring action of the spring plate 55 and is rotated counterclockwise in the drawing. When the advancing unit 54 has traveled a fill stroke, the protrusion 56a passes the position of the protruding plate 54a. When the protrusion 56a passes the position of the protruding plate 54a, the advancing unit 54 becomes free, and the advancing unit 54 subjected to the force of the spring 55 returns to its original position as shown in the figure.
An advancing tab 57 is located on the advancing unit 54. This advancing tab 57 makes elastic contact with the sheet of staples S extending from the cartridge 50. Therefore, the rotation of the advancing unit 54 causes the advancing tab 57 to advance the sheet of staples S in the direction of the driver 56. When the advancing unit 54 rotates counterclockwise, the advancing tab 57 makes and maintains elastic contact with the sheet of staples S. When the advancing unit 54 rotates counterclockwise, force is applied to return the sheet of staples S. However, the reverse motion stopping tab 52a prevents the sheet of staples from returning.
Often several cartridges are provided containing rolled sheets of staples of varying lengths. These cartridges can be replaced to provide the desired type of staples.
When a cartridge 50 is replaced in a stapler, the cartridge 50 is removed with the advancing tab 57 bearing down on the sheet of staples S. When a cartridge 50 is removed with the advancing tab 57 bearing down on the sheet of staples S, the sheet of staples S is pulled out from the cartridge 50. Because the revere movement stopping tab 52s bears down on the pulled out sheet of staples S, the staples do not return to their original position. As a result, some of the staples in the sheet of staples S are wasted.
Sometimes the cartridge 50 is divided in two and only the sheet of staples in the housing unit is replaced. However, even though the cartridge 50 is divided in two, the reverse motion stopping tab 52a continues to function and the section of the sheet of staples S drawn out by the reverse motion stopping tab 52a does not return to its original position. As a result, the section of the sheet of staples is wasted.
Therefore, there remains a need for a stapler that does not waste any staples when a staple cartridge or sheet of staples is replaced.
The invention relates to a stapler device including a frame and a mounting unit configured to be selectively attached to and removed from the frame. The mounting unit includes a staple cartridge, a staple advancing mechanism, a staple former, and a staple driver. In one embodiment, the stapler device further includes a motor coupled to the frame.
In one aspect of the invention, the staple cartridge is configured to be removed from a portion of the mounting unit including the staple advancing mechanism, the staple former, and the staple driver when the mounting unit is removed from the frame. In another aspect of the invention, when the mounting unit is attached to the frame, the staple advancing mechanism is in a first position that permits the staple advancing mechanism to engage staples to be fed from the staple cartridge, and when the mounting unit is removed from the frame, the staple advancing mechanism is in a second position that prevents the staple advancing mechanism from engaging the staples to be fed from the staple cartridge. The staple advancing mechanism can be automatically movable between the first and second positions when the mounting unit is attached to and removed from the frame.
In yet another aspect of the invention, the mounting unit further includes a reverse motion stopping mechanism. The reverse motion stopping mechanism is engaged with staples to be fed from the staple cartridge when the mounting unit is attached to the frame, and the reverse motion stopping mechanism is disengaged from the staples to be fed from the staple cartridge when the mounting unit is removed from the frame. The reverse motion stopping mechanism can be automatically engaged with the staples to be fed from the staple cartridge when the mounting unit is attached to the frame, and the reverse motion stopping mechanism can be automatically disengaged from the staples to be fed from the staple cartridge when the mounting unit is removed from the frame.
The invention also relates to a method of removing a staple cartridge from a stapler device having a frame and a mounting unit configured to be selectively attached to and removed from the frame. The mounting unit includes a staple advancing mechanism, a staple former, a staple driver, and the staple cartridge. The method includes removing the mounting unit from the frame such that each of the staple advancing mechanism, the staple former, the staple driver, and the staple cartridge are separated from the frame but remain coupled together in the mounting unit. In one aspect, the method further includes, after removing the mounting unit from the frame, removing the staple cartridge from a portion of the mounting unit including the staple advancing mechanism, the staple former, and the staple driver.
The invention further relates to a stapler device having a frame and a mounting unit configured to be selectively attached to and removed from the frame. The mounting unit includes a staple cartridge, a staple former, and a staple driver. The staple cartridge is further removable from a portion of the mounting unit including the staple former and the staple driver when the mounting unit is removed from the frame to permit replacement of the staple cartridge of the mounting unit. In one aspect of the invention, the mounting unit further includes one or both of a staple advancing mechanism and a reverse motion stopping mechanism.
The invention also relates to a method of removing a staple cartridge from a stapler device having a frame and a mounting unit configured to be selectively attached to and removed from the frame. The mounting unit includes a staple former, a staple driver, and the staple cartridge. The method includes removing the mounting unit from the frame such that each of the staple former, the staple driver, and the staple cartridge are separated from the frame but remain coupled together in the mounting unit. After removing the mounting unit from the frame, the method further includes removing the staple cartridge from a portion of the mounting unit including the staple former and the staple driver to permit replacement of the staple cartridge of the mounting unit.
In one aspect of the invention, the mounting unit further includes a staple advancing mechanism positioned to be engaged with staples to be fed from the staple cartridge when the mounting unit is attached to the frame. Removing the mounting unit from the frame includes automatically repositioning the staple advancing mechanism so that the staple advancing mechanism cannot engage the staples to be fed from the staple cartridge.
In another aspect of the invention, the mounting unit further includes a reverse motion stopping mechanism engaged with staples to be fed from the staple cartridge when the mounting unit is attached to the frame. Removing the mounting unit from the frame includes automatically disengaging the reverse motion stopping mechanism from the staples to be fed from the staple cartridge.